Make dependancy adal optional

[iamneha]

Fixes issue :kubernetes-client/python/issues#645
To fix this issue:

1. remove adal from requirements
2. add adal to extras_require in setup.py
3. handle import error

Fix for 1 and 2 is kubernetes-client/python/pull#668

[iamneha]

/cc @tomplus @roycaihw @dims

[codecov-io]

Codecov Report

Merging #108 into master will decrease coverage by 0.3%.
The diff coverage is 11.76%.

@@            Coverage Diff             @@
##           master     #108      +/-   ##
==========================================
- Coverage   92.04%   91.74%   -0.31%     
==========================================
  Files          13       13              
  Lines        1182     1187       +5     
==========================================
+ Hits         1088     1089       +1     
- Misses         94       98       +4

Impacted Files	Coverage Δ
config/kube_config.py	83.22% <11.76%> (-1.02%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 5c242ea...cfae0d6. Read the comment docs.

[tomplus]

BTW, there is a similar PR: #101

[iamneha]

BTW, there is a similar PR: #101

I don't know how this happened I always assign myself to issue I am working on.
I think @micw523 started this after I raised my first PR.

[micw523]

Per our slack discussion on Oct 31st, I asked you if you wanted to hand over the issue and you said yes. That was why I started to work on it and opened a PR.

If you want to work on it again, go straight ahead. I don’t mind - to me reviewing is just important as submitting a fix. However in the future please remember what you have said so that this situation does not happen any more.

[iamneha]

Per our slack discussion on Oct 31st, I asked you if you wanted to hand over the issue and you said yes. That was why I started to work on it and opened a PR.

Yes @micw523 you asked me the issue you were working on but I think you are confusing this issue with another one you asked for
This is the issue you asked for " Loading yaml file "

If you want to work on it again, go straight ahead. I don’t mind - to me reviewing is just important as submitting a fix. However in the future please remember what you have said so that this situation does not happen any more.

I think we should start working on issue after assigning ourselves. I would have stopped working on it if you mentioned that you are working on it.

No worries, if you still want to work on it please assign yourself to that issue and I'm happy to help you with the issue :)

[dims]

@iamneha @micw523 i left a note in #101

[roycaihw]

/lgtm

@iamneha @micw523 Thanks for working on this :)

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

Approval requirements bypassed by manually added approval.

This pull-request has been approved by: iamneha

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment